Ok, you've eliminated the octy and now have two 'extra' fuel line connections; what to do? Some just loop a length of fuel hose between them, some use two short pieces of hose and plug them with a bolt or something, some fill them with some sort of goo. Here's a bit more elegant solution, and likely cheaper too!

This will convert your petcock to full manual, and eliminate the 'prime' position (converting it to another 'off'), as well as sealing it. Simply run a 5m/.8 pitch tap into the 'prime' feed hole as shown (you don't even need to drill; it's big enough), then thread a same-size set screw into it. I used a 10mm long screw, but a 5mm would be better and don't run the tap in as far as I did. Thread it just deep enough so that the screw goes in flush. I put some teflon tape on, and it's sealed. If you want to reinstall the octy, just pull the screw.

The optional 1/4" ID rubber cap is just for 'finish' and to keep the spigot clean for future; gas won't get to it. The screws were only $.75 for both.

This could also be done to the standard petcock (with a larger screw), but would require other internal mods. And if you want to replace those always-rusty small screws that hold on the chrome cover, run a 6-32 tap through the holes and use some stainless buttonheads. Again, you don't even need to drill (but you do need to enlarge the holes on the cover), just run the tap through. You can do this to either type petcock...